A recent study has discovered that omega-3 fatty acids can significantly reduce symptoms of depression and anxiety in young mice subjected to stress, with the mice exhibiting both behavioral and molecular changes. This finding, published in Neurobiology of Stress, offers hope for new treatments for adolescent depression in humans.
Major depressive disorder is a debilitating mental health condition that has increasingly been affecting young adults globally, particularly due to the COVID-19 pandemic.
While adults have various treatment options, adolescents often find these therapies ineffective, or even harmful. The search for alternative treatments has led researchers to explore the potential benefits of omega-3 fatty acids, commonly found in fish oil, and known for their anti-inflammatory properties.
Hence, the study aimed to understand whether omega-3 could counteract the effects of stress-induced depression in juvenile mice. Stress is a well-known trigger for depression, and the researchers used ultrasound frequencies to simulate emotionally stressful conditions that led to depressive-like behaviors in the mice.
The methodology involved exposing 40 one-month-old mice to alternating ultrasound frequencies for three weeks, mimicking negative (20–25 kilohertz) and neutral (25–45 kilohertz) emotional states. Concurrently, the mice were given a diet either with omega-3 supplements, containing both eicosapentaenoic acid and docosahexaenoic acid, or a ‘dummy’ supplement not containing any omega-3 (a placebo).
The results were promising. Mice treated with omega-3 showed a marked improvement in behavior, displaying less anxiety-like and depressive-like symptoms compared to those on a regular diet.
Specifically, the group of mice that were provided the placebo demonstrated a reduced preference for consuming freely-available sugar water. This indicated anhedonia (an inability to experience pleasure with activities that usually bring pleasure), which is a key symptom of depression.
Furthermore, mice that consumed omega-3 exhibited less anxiety-like behaviors. For example, when placed in an empty square box, the mice were more adventurous and spent more time in the center of the “open field”.
Omega-3 intake also led to changes in metabolism in the brain, blood, and liver, as well as a decrease in pro-inflammatory cytokines, suggesting a molecular basis for the behavioral improvements.
However, levels of the hormone cortisone, which was induced by stress from the ultrasound, remained at high levels.
“This discrepancy suggests that while omega-3 can mitigate some inflammatory responses, it may not affect all stress-related hormonal pathways. [Omega-3 influences] several parameters that stress had not altered, which independently appear to exert a protective effect,” the authors noted.
It is important to note that while these findings are encouraging, they come with limitations. The primary concern is whether the results from a mouse model can be translated to humans.
The study, “Omega-3 alleviates behavioral and molecular changes in a mouse model of stress-induced juvenile depression,” was authored by Tatyana Strekalova, Daniel Radford-Smith, Isobel K. Dunstan, Anna Gorlova, Evgeniy Svirin, Elisaveta Sheveleva, Alisa Burova, Sergey Morozov, Aleksey Lyundup, Gregor Berger, Daniel C. Anthony, and Susanne Walitza.